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Heat advisory until Wednesday

Temperatures on Long Island could reach 100 degrees this week. Newsday TV's meteorologist Rich Von Ohlen reports. Credit: Newsday

Long Island's summer of 2025, a scorcher so far, is on pace to be even hotter Tuesday, with an extreme heat warning in effect through the evening and more poor air quality to go along with it, officials said.

The National Weather Service issued the heat warning for Nassau and western Suffolk. Temperatures islandwide could feel as hot as 110 degrees in some spots on Tuesday, according to the National Weather Service.

Monday gave Islanders a hint of what's to come.

Temperatures peaked in the low 90s, but the humidity levels made temperatures feel in the upper 90s or even 100, meteorologist Jay Engle with the weather service's Upton office told Newsday.

Air quality will continue its downward trend Tuesday because of a spike in ozone levels, according to the New York State Department of Environmental Conservation. 

Nassau and western Suffolk could see highs between 97 and 103 degrees on Tuesday, and heat indexes, or "feels like" temperatures, between 105 and 110 degrees, the weather service said in the extreme heat warning bulletin. Areas in eastern Suffolk, which will be under a heat advisory Tuesday will fare slightly cooler, with temperatures between 90 and 99 degrees and heat indices between 95 and 104 degrees. The conditions will peak sometime between noon and 8 p.m. 

Anyone spending time outside Tuesday may also be exposed to increased levels of ozone, a ground-level pollutant that forms in the summer heat when sunlight reacts with vehicle emissions and other industrial pollutants, according to the DEC. Individuals of the groups sensitive to the high heat and humidity — seniors, young children and anyone with respiratory or cardiovascular conditions — are similarly at greater risk of feeling the effects of the respiratory irritant.

Intense outdoor activities should be rescheduled to the early morning or evening hours on Tuesday, according to the weather services' extreme heat warning. Stay hydrated, use air conditioning or seek shelter in cool locations, and wear light, loose-fitting clothing.

On Monday, near the sweaty start of a heat wave expected to last days, several Long Island school districts said that they would monitor classroom temperatures and take other steps, but Regents exams – which are scheduled through Wednesday – would continue.

Lindenhurst officials said testing locations were changing to classrooms with air conditioning.

In West Hempstead, Superintendent Dan Rehman wrote in a letter to district families that finals and Regents were proceeding as scheduled, with mandatory attendance. Students will “cycle through air-conditioned rooms” and some outdoor activities could be moved inside, he wrote. Additionally, parents and guardians have the option of keeping children home or picking them up early.

Central Islip administrators wrote in a post on X Monday that Regents and finals would continue but that testing classrooms would be monitored. Elementary schools will use fans, water breaks and room changes.

Malverne administrators said on X that, because of the heat, students would check in for Regents in the performing arts center.

The press office for the New York State Education Department did not respond to a request for comment, but in a May memo to school administrators, Zachary Warner, the department’s assistant commissioner for the office of state assessment, said there were “no provisions for weather-related cancellation or rescheduling” of June and August Regents exams but that schools could change exam locations because of conditions like extreme heat.

Newsday's Maureen Mullarkey and Nicholas Spangler contributed to this story.

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